Casing for resistances.



A. W. BERRESPORD.

CASING FOR RESISTANCES.

APPLICATION FILED JULY 10, 1909.

Patented Dec. 9, 1913.

I 124:3)": J rz /klrWzfgerg'ey amag 3 (20%.

WIT $535,365

' To ollt whom it may concern:

" Be it known'that I, ARTHUR W. Burmes- STATES rigour owner-i,

ABTHUB W. B-ERBESIORD, F IILWAUIEE, WISCDNGIN, ABSIGNQB TO THE CUTLER-HAHKER MFG. 60., OF MILWAUKEE, WISCONSIN, A GDRPORAT-IQN 0F WISCONSIN.

GASIHfi EUR BESISTANCES.

FORD, a citizen'of the United States, residing at Milwaukee, 1n thecounty of Milwaukee fend State of Wisconsin, have invented new anduseful Improvements in Casings for I Resistances, of which the followingis a full,

clear, concise, and exact description, reference being had totheaccompanying drawing, forming a part of this specification.

My invention relates to improvements in L lIlClOSlIlg casings forresistances.

v "Vh'ere resistances are inclosed for the pur pose of protection it iscustomary to provide apertures in the inclosing casing to permit a. freecirculation of air between the resistance 11111138 to prevent the samefrom overheating. Such apertures a're usual y provided in the top andbottom of the casing as this arrangement insures the best ventilation.Even though inolosed resistances are ell'yentilated, they are,nevertheless, apt to become overheated and burn out. 7 This [causes theformation of arcs tending to pass upwardly through the apertures in thetop of the casing. Furthermore, uponburuing out of the resistancesmolten resistance material and solder flow through the open tures in thebottom of the casing. Consequently, with ordinary inclosing casingsthere is great danger of starting fires upon 5 the burning outof theresistances. 4

My invention, therefore, has for its object t to provide a casing whichwill insure proper ventilation ofthe resistances and also pre- "vent theescapement of any flames or molten material therefrom upon the burningfont of the resistances.

For the purpose of the nature of my invention, I shall describe theemhodiziielit thereof illustrated in the accompanying drawing. It shouldbe under.-

:stood, however, that my invention is not limited to the particularstructure shown in the drawing, but is capable. of various modifieations.

plied .theretMFigs, 2 and 3 are perspective 9 In the drowing, Figure 1iso perspeotiye view of e device having my invention apvlews of parts ofthe device. l is a on i l se ti na i taken through aportion'oi the.device; and Fig. 5 is a permore fully disclosing v lnecimtion of LettersPatent. Application filed July 10,1909. Serial No. 506,934.

1 sides of the I have shown lugs 12 having angular por-i Patented Dec.9-; 1913.

of which I shah now des ribe- In racti e, the asing m y ass me variousdiflerent forms. The particular casing illustrated is in the form of arectangular box, being provided with a back 8,' side xpieces 9, a to anda bottom 11. The QX may be ormed of any preferred size and of anypreferred material, Furthermore, the box'ma be constructed in variousiifirent ways, illustrated, the buck and are formed integrally, whilethe top end bottom thereof are formed of separate pieces. For supportingthe casing,

tions to Whichth sides and top and bottom of the hex are secured-bysuitable means,

such as rivets 13 or screws 14*. In practice, the resistance unitsmey bemounted either in the casing or on the hack of the insulating panel 4;.However, it is customary to mount the units in the casing. This may bedone in various difiierent Ways. One method of mounting the resistanceunits in the cas in is shown in Fig. 2, As illustrated in this figure"the resistance units 15 are mounted vertically in the casing and spaceda suitable distance apart, To insure proper ven tilation of the units15, I have provided apertures 18 inthe top and bottom of the ossing Thispermits a free circulation. of air-through the casing, to preventoverheating of the units 15.

To prevent escapement of molten metal through the apertures in thebottom of the casing, I preferably provide :1- receptacle 19 adapted tobe secured to the underside of the bottom portion 11 in any preferredmanner. As illustrated, the rece itacle l9 n erely nomprises an oblongpan of the some w dth and depth asthe casing and having inolined sideport ons, For secur ng the receptacle 19 to the casing I have shownscrews 20 adapted to fit into screw threaded apertures 21. in the bottomportion It. In order to prevent. the receptacle 19 from obstructing thecirculation ot air through the ventilating apertures, I preferablyprovide spacing washers 2L surrounding the screws 20 which maintain thereceptacle It) at. a suitable distance from underside of the casing.

For preventing the escapenient of flames from the casing, upon burningout of the resistance units, l. have provided a hood, the structure ofwhich .1 shall now des ribe. This hood comprises an outer portion 25 andan inner portion 26. The hood is preterabLv of substantially the samewidth and deptlnas the top It) oi the casing and is adapted o restdirectlygthereon. The opposite endsol the inneiganil outer members areclosed, while the other ends thereot are open, thereby providing atortuous line for the eseapement of air and gases passing through theapertures in the top of the casii'ig. In practice, the hood may be.formed in any preferred manner and securml to the casing by anypreferred means. As illustrated, the hood is adapted to be secured tothe casing by means of a screw :27 adapted to tit into a screw threadedaperture 28 in the top 10 of the casing. The hood is preferably arrangedto snugly titbet ween. the supportinglugs at opposite sides of thecasing so as to prevent the same turning. The portion 26 of the hood inreality forms a ba'tlie plate for detlecting any flames produced uponthe burning out of the resistances. The path provided for such flames,as indicated by ar rows, insures the cxtinguishmcnt thereof bclore thecan leave the hood. While it may appear that the hood obstructs thecirculation of air for ventilation, it has been found in practice thatit does not deso to any appreciable extent. (-oi'isequent-ly, the casingthus produced not only provides for proper ventilation, but obviates alldanger arising from the production of flames and molten metal. upon theburning out. of the resistances.

In Fig. 5, l have illustrated the preferred manner of 'l'orn'iing themember 2G ot the hood. This construction provides upwardly extending'ide pieces 30 which form means for maintaining the members 2a and 25 ina spaced relation without the use of any speial fastening means.

Having thus described myinvcntion what I claim as new and desire tosecure by Letters Patent is 1. An inclosing easing tor resistanceshaving a reflex ventilating flue.

Q. Arheostat comprising a resistance ele ment ,"an inclosing casingtherefor, said casing having ventilating openings in its top the' ingventilating apertures in the top thereof and a hood arranged on the topthereof, said hood having a tortuous flue therein.

Au iuclosing casing for resistances comprising a box portion havingventilating apertures in the top and bottom thereof, a hood arranged onthe top of said boX portion and having a. ballle plate arranged thereinand a hollow recepta le disposed below the apertures in the bottom ofsaid box portion.

ti. A hood for resistance inclosing casings having a reflex openingtherein.

7. hood for resistance inclosing casings comprising an elongated membersubstantially U-shape in cross section and closed at one end and abatlle plate arranged within said number to term a tortuous fine.

8. A" hood for resistance inclosing casings comprising two elongatedportions substantially Ushape in cross section, and arranged one withinthe other, said portions having opposite ends thereof closed and beingspaced from one another to form a tortuous tine.

t). In a rlieostat, the combination with a box body having open ends, ofa pair of plates closing said ends and held by the box body, resistancecoils supported between said plates, said plates having ventilatingapertures therein, and guard-pieces covering the ends of the box body ata distance from said plates leaving a space between the said ends of thebox body and the plates, said space conninmicating with the atmosphere,Whereby a circulation oi air is permitted.

it). in a rlieostat, the combination with a box body ha ving top andbottom plates provided with ventilating apertures therein, re-

sistance coils supported by and between said plates and removable guardp eces covering the apertures in said plates, said guard pieces and saidplates being spaced to permit circulation of air through the ventilatingapertu es in said plates.

11, in a rheostat, in (annbination, an insulating panel for theresistance controlling contacts, a resistance casing secured to saidinsulating panel, said casing having top and bottom plates provided withventilating apert ures therein, said casing and said panel togetherforming an entir ly closed receptacle except for the ventilatingapertures in In Witness whereof, I have hereunto subthe top and bottomplates, resistance units scribed my name in the presence of twowitsupported between said plates, and top and nesses.

bottom guard members covering the ventilat- ARTHUR W. BERRESFORD. ingapertures in said plates but spaced from Witnesses:

said plates to permit circulation of air FRANK H. HUBBARD,

through the ventilating apertures therein. S. V.FI'1-ZGERALD.

